Circulation ports for drill bit



C. M. KUCERA ETAL CIRCULATION PORTS FOR DRILL BIT Filed June 2, 1959 flow/e/ A. De/ Y/omme C/emenz M Kacera INVENTORS A E, M

Arralwv K! July 30, 1963 3,699,324 CIR'CULATHGN PQRTS FQR DRKLL BIT Clement M. Kueera and Daniel L. DelHomme, Houston, Tex., assignors to Reed Roller Bit Company, Houston, Tex., a corporation of Texas Filed June 2, H59, Ser. No. 817,576) 2 Claims. (Cl. 175-339) This invention relates generally to drill bits, and more particularly to roller bits for drilling deep wells.

Roller bits now in common use embody a bit head in which rollers are rotatably mounted. The bit head is connected to the end of a drill stem which is rotated to cause the rollers to roll upon the bottom of the hole and thereby cut or :crush the formation. A mud laden drilling fluid is pumped downwardly through the drill stem and bit, and rises upwardly to the surface of the earth in the space between the drill stem and the wall of the hole.

One of the most important desired functions of the drilling fluid thus circulating is quickly to remove the cut or crushed particles of the formation from the bottom of the hole and the roller cutters and from the areas therearound. This function is not always efliciently performed, because in various formations, particularly in sticky shales, particles of the formation may adhere to the rollers, and accumulate between the rollers and the adjacent parts of the bit head, and in the area above the rollers, as a result of which the rollers may either cease to rotate and be worn by skidding upon the bottom of the hole, or the abrasive particles of the formation may erode away the adjacent stationary parts of the bit head.

This invention has for one of its general objects the provision of a new and improved roller bit head through and around which the drilling fluid and cuttings may freely circulate.

Another object is to provide new and improved drill bit to alleviate packing or balling up of the bit head with dislodged cuttings.

Another object of this invention is to provide new and improved roller cutter support through which drilling fluid or formation particles may circulate from the area above the roller cuttens to the space between the bit head and the wall of the bore hole being drilled.

Other objects will hereinafter appear.

The preferred embodiment of this invention is illustrated by the accompanying drawings in which:

FIG. 1 is a bottom plan view of a cone-type roller drill bit.

FIG. 2 is a side elevation view, partly in section, of the bit shown in FIG. 1.

FIG. 3 is a sectional view taken along line 3-3 of FIG. 2.

Referring to the drawings, the drill bit head is indicated at 1. It may be provided with the usual hollow threaded shank 2 for attachment to the drill stem (not shown). The bit head 1 has downardly extending bearing extensions 3, 4 and 5. Roller cutters 6, 7 and 8 are rotatably mounted on the bearing extensions 3, 4 and 5, respectively, on axes inclined downwardly and inwardly from the said extensions. The roller cutters 6, 7 and 8 are rotatably mounted and retained on the bearing extensions 3, 4 and respectively, in the usual manner.

Drilling fluid pumped downwardly through the drill stem (not shown) passes into the hollow of the threaded shank 2 and thence through fluid discharge passageways 10, 11 and 12 to be discharged downwardly toward the dfldhfifi Patented July 30, 1963 2 bottom of the hole. During the drilling operation particles of dislodged formation may accumulate in the area 13 above the roller cutters 6, '7 and 8. This accumulation of cuttings may become so severe that the cutters may not roll fireely, which condition is commonly known as balling up.

in order to alleviate this balling up condition and to scavenge the area 13 more eflioiently, the bearing extensions 3, 4 and 5 are provided with passageways 14-, 15 and 16, respectively, adjacent the upper outer portions of each of the roller cutters 6, 7 and 8.

In FIG. 3 the cutters s, 7 and 8 are shown diagnamatically. The bearing extension 3, which is similar to bearing extensions and 5, has a passageway 14 therethrough. The axis of the passageway 14 is offset or inclined from L16 centerline or longitudinal axis of the bit in a forward direction with respect to the bit rotation. The axes of the passageways it, 15 and re are arranged so that they lie tangent to an imaginary circle 17 about the centerline or longitudinal axis of the drill hit. As is shown in FIG. 2, the passageway E i may be inclined upwardly from the longitudinal axis of the bit.

In operation, as the bit is rotated, the cutting-laden drilling fluid in the area 13 above the cutters 6, 7 and 8 is urged outwardly by centrifugal force and by an aspirating efiect, produced by such rotation, at the outer ends of the passageways 14-, 15 and 16. The passageways 14, 15 and 16, being inclined forwardly with respect to the rotating axis of the drill bit, further tend to urge the cuttings into the passageways i4, 15 and 16 to be centrifugally pumped outwardly therethrough into the annular space between the bit head and the wall of the bore hole being drilled.

It will be apparent that this invention finds particular utility in so-called jet bits which have passageways discharging fluid downwardly near the wall of the bore hole.

This invention is not limited to the embodiment herein disclosed. Various changes, within the scope of the following claims, will occur to those skilled in the art.

We claim:

1. A cone bit having a head, said head having three downwardly extending bearing extensions, a substantially conical roller cutter rotatably mounted on each of the said bearing extensions, said head having fluid discharge means to discharge fluid toward the bottom of the bore hole, each of the said bearing extension having a passage way therethrough adjacent the upper outer portion of the roller cutter mounted thereon, the longitudinal axis of each of the said passageways being offset from the longitudinal axis of the bit in a forward direction with respect to the bit rotation.

2. A drill bit having a head, said head having a plurality 0t downwardly extending bearing extensions, a roller cutter mounted on each of the said bearing extensions, at least one of the said bearing extensions having a passageway therethrough adjacent the upper outer portion of the roller cutter mounted thereon, the axis of the said passageway being directed to the forward side of the longitudinal axis of the drill bit with respect to the bit rotation.

Kucena et al Oct. 19, 1954 Williams Jan. 1, 1957 

2. A DRILL BIT HAVING A HEAD, SAID HEAD HAVING A PLURALITY OF DOWNWARDLY EXTENDING BEARING EXTENSIONS, A ROLLER CUTTER MOUNTED ON EACH OF THE SAID BEARING EXTENSIONS, AT LEAST ONE OF THE SAID BEARING EXTENSIONS HAVING A PASSAGEWAY THERETHROUGH ADJACENT THE UPPER OUTER PORTION OF THE ROLLER CUTTER MOUNTED THEREON, THE AXIS OF THE SAID PASSAGEWAY BEING DIRECTED TO THE FORWARD SIDE OF THE LONGITUDINAL AXIS OF THE DRILL BIT WITH RESPECT TO THE BIT ROTATION. 